Just two hours of TV a day doubles risk of child obesity

Children who watch more than two hours of TV a day are twice as likely to be obese and suffer high blood pressure, say researchers.

A U.S. study found those glued to the screen for between two and four hours a day were 2.5 times more likely to have hypertension, which can lead to heart disease and stroke in later life.

That increased to 3.3 times the risk for children watching TV for four hours or more each day, says a report today in the American Journal of Preventive Medicine.

The study also found that children tended to be more seriously overweight the more time they spent watching TV.

There are fears that 'couch potato' children are not only physically inactive but also exposed to TV commercials selling high-fat and other junk foods.

The study's authors examined 546 children aged four to 17, who were evaluated for obesity at child health clinics in California from 2003 to 2005.

Even after allowing for obesity, those who spent more time watching TV were at greater risk of high blood pressure.

But Dr Stuart Biddle, from the School of Sport and Exercise Sciences, Loughborough University, told the journal that the causes of childhood obesity were more complex than simply watching too much TV.

He said: "Obesity levels are increasing but TV viewing figures are not; obesity increases during adolescence at the same time that TV viewing decreases; and boys watch more TV than girls but show less obesity and greater physical activity."